Year	Percent
1991	2.458
1992	2.542
1993	2.667
1994	2.782
1995	2.814
1996	2.739
1997	3.231
1998	3.003
1999	3.072
2000	3.077
2001	2.611
2002	2.553
2003	2.548
2004	2.705
2005	2.847
2006	2.679
2007	2.831
2008	2.745
2009	2.819
2010	2.634
2011	2.46
2012	2.789
2013	3.283
2014	3.574
2015	3.361
2016	3.702
2017	3.727
2018	3.656
2019	3.582
2020	3.521
2021	3.464
2022	3.411